As a conventional technology, a known angular velocity (rate) detecting device disclosed by the Specification of U.S. Pat. No. 5,945,599 (Patent Document 1) has an exciter (drive frame) supported by using a plurality of supporting beams and fixed beams extending outward the exciter in a detecting direction orthogonal to an exciting direction and holding the exciter. Since the supporting beam and the fixed beam are flexible in the exciting direction and rigid in the detecting direction, they are capable of making the exciter easy to move in the exciting direction and hard to move in the detecting direction. And, the Coriolis component is coupled with the exciter by a beam flexible in the detecting direction and rigid in the exciting direction. Therefore, the Coriolis component vibrates together with the exciter following the movement of the exciter in the exciting direction.
When an angular velocity is applied about an axis orthogonal to the exciting direction and the detecting direction in this state, the Coriolis force proportional to the angular velocity applied in the detecting direction that is orthogonal to the exciting direction is applied to the vibrating exciter and the Coriolis component. Meanwhile, since the exciter is formed to be hard to move in the detecting direction, only the Coriolis component is displaced in the detecting direction. By detecting the displacement of the Coriolis component or the Coriolis force, the angular velocity can be detected.
However, in the case where a vibrating body is supported by holding the exciter, a distance between support points tends to be long, and thus when strain by mounting and strain by heat of a substrate supporting the vibrating body are generated, elastic stress is generated onto the fixed beam and the supporting beam to change the spring constant of the beam largely, thereby deteriorating the performance of angular velocity detection.
A known angular velocity detecting device disclosed by the Specification of Japanese Patent Application Laid-Open Publication No. 2000-180174 (Patent Document 2) has four exciting components (drive frame) which are also Coriolis components arranged radially and fixed to a supporting substrate (basement layer) symmetrically about a center point. Therefore, even when strain by mounting and deformation of substrate by heat are generated, no elastic stress is generated onto the supporting beam and the fixed beam, thereby maintaining the essential performance.
However, there is a limitation in the shape to be symmetrical about a center point, and accordingly, electrodes should be provided far because the space for providing electrodes is narrower close to the center point, and bad usability of space, and thus it is not suitable to make small. Further, since the support and fixation are made at only the center point, it is easy to pose deflection by the structure's own weight, and weak in disturbance because it easily vibrates outward of the substrate surface. In the case where an active layer is thin (e.g., 4 μm), a suspension structure formed on the active layer and the supporting substrate at the stage of manufacture possibly be stuck, which poses yield reduction.